Cyclophosphamide and ifosfamide are commonly used anticancer agents. A major limiting factor in their use is the resulting bladder toxicity which can lead to ongoing bladder pain, urgency and dysuria. A major metabolite of these drugs, acrolein, is toxic to human urothelial cells, reducing cell survival and increasing damaging reactive oxygen species (ROS) formation.

Aim:

To investigate whether N-acetylcysteine or Vitamin C can protect human bladder urothelial cells from damage due to acrolein.

Methods:

Human bladder urothelial cells (RT4 and T24) were treated with acrolein (100µM) alone or in combination with N-acetylcysteine or Vitamin C (0-3mM) for 24 hours. A matched untreated control was also included for each group. Following treatment, cell survival and ROS formation were measured.

Results:

Acrolein (100µM) reduced cell survival by 65±6% in RT4 cells (p<0.05) and 93±1% in T24 cells (p<0.01). The reduction in cell survival due to acrolein was completely abolished in the presence of N-acetylcysteine (1mM) (p<0.001). Basal ROS levels were increased by 10±5% in acrolein (100µM) treated RT4 cells. N-acetylcysteine (1mM) not only prevented the increase in ROS production induced by acrolein but inhibited basal ROS production by 69±1% (p<0.01). Cell survival in acrolein treated T24 cells was too low to allow accurate measurement of ROS production. Vitamin C had no protective effects but at a concentration of 3mM had a pro-oxidant effect leading to increase ROS formation and decreased cell viability (p<0.05).

Conclusions:

N-acetylcysteine appears to protect human bladder urothelial cells from damage caused by the cyclophosphamide and ifosfamide toxic metabolite acrolein. Vitamin C has antioxidant properties but does not protect the urothelial cells. N-acetylcysteine can be given as an oral supplement and may have benefits for patients receiving cyclophosphamide and ifosfamide, potentially reducing bladder urothelial cell damage and uro-toxic side effects.